The field of the disclosure relates generally to turboprop assemblies and, more particularly, to a profile of an intake port for turboprop assemblies.
Most known air inlets for turboprops are positioned a distance behind propellers to receive air for a turboprop engine. Known turboprop air intake ports are shaped with a curved inlet lip that lies on a geometric plane substantially normal to the mean airflow from the propellers. When a propeller passes in front of the intake port, aerodynamic loading increases temporarily until the propeller rotates away from the intake port. Airflow around the propeller reacts with fluctuations in the surface forces on the propeller that radiates acoustically and causes an increase in noise generated by the propeller. Furthermore, the airflow on the propeller can weaken during this interaction effect, thereby increasing the flow distortion in the propeller wakes which propagate and hit the lip of the inlet, thereby creating a pressure fluctuation that radiates acoustically, causing a further increase in the noise generated. The unsteady aerodynamic interaction between the propeller and air inlet on a typical turboprop assembly leads to additional sound generation, thereby adding to sound annoyance for passengers on the aircraft and communities on the ground.